Control unit for dental handpieces



y 1966 J. A. WILSON, JR 3,250,006

CONTROL UNIT FOR DENTAL HANDPIECES Filed Aug. 25, 1961 2 Sheets-Sheet l 75 low Speed Hand Diem 707/591? Speed Hanapz'ece /6'4 lows Deed l /and oiece INVENTOR. (Jesse f1 M150) Jr.

May 10, 1966 .1. A. WILSON, JR

CONTROL UNIT FOR DENTAL HANDPIECES 2 Sheets-Sheet 2 Filed Aug. 23, 1961 4 5 5 1 w 1 1 M w T.7 A 9 m A w m fi 1 ym $flw en wfiz W M W w United States Patent 3,250,006 CONTROL UNIT FOR DENTAL HANDPIECES Jesse A. Wilson, Jr., Palatine, Ill., assignor to Herbert Ascher, doing business as The Adsco'Compauy, Chicago, Ill.

Filed Aug. 23, 1961, Ser. No. 133,510 1 Claim. (Cl. 32--28) This invention relates to apparatus for controlling the operation of dental instruments and, more particularly, to apparatus for controlling the operation of air turbinedriven handpieces and related dental equipment.

The advent of air turbine-driven rotary hand instruments or handpieces for dental drilling operations and the like and the concomitant arrival of ultra-high speed rotary instruments have results in the employment by the well-equipped dentist of a combination of handpieces adaptable to provide speeds in the upper and lower ranges. Thus, the dentist will usually have a low torque, high rotary speed instrument for achieving greater efiiciency and speed in cutting tooth structure and a high torque, lower rotary speed handpiece for excavating caries and for certain refining and finishing operations. A third handpiece with a reduced head size may also be employed for use on 'childrens teeth. In addition to handpieces, substantially all dentists employ a syringe or syringe-like device for injecting water, air, or water spray in the patients mouth and they often use a dental chipblower, which generally comprises an extra air nozzle located in the head of a handpiece.

Since the handpieces are powered by turbines driven by air and utilize Water or water spray as a coolant during drilling and other operations, all of the instruments mentioned above, except the chipblower, require both an air and a water supply. Heretofore, however, each of these instruments has been operated wholly independently of the other by separate control means, and each has employed separate fittings for connection with water, air, and electrical sources. This has resulted in the need for considerable amounts of tubing and wiring and in the duplicationand triplication of, among other things, such devices as foot controls, air and water pressure regulators, air pressure gauges, air and water filters, and water heaters. Installations of certain new equipment, therefore, have often been hampered and even prevented in the small dental operatories; and in the large operatories such installations have frequently caused undesirable crowding or cluttering, which in many instances offset, at least to some extent, the operating efiiciency gained by the use of new instruments and which sometimes had an upsetting or unsoothing effect upon the dentists patients.

Accordingly, it is an important object of this invention to provide in one compact unit apparatus for controlling a plurality of dental air turbine handpieces and relatedequipment, such as a dental syringe and a dental chipblower.

An additional object of this invention is to provide apparatus for controlling the aforementioned dental instruments, which occupies a minimum amount of space in the dental operatory and which is fully automatic so as to afford the dentist considerable savings of time, motion, and energy.

It is still another object of this invention to provide apparatus for controlling the aforementioned dental-instruments, which eliminates cumbersome excess tubing and wiring; affords simpler, neater and less expensive installation; and contributes to the overall attractiveness of the dentists operatory and to a favorable psychic effect on the patient.

A further object of this invention is to provide apparatus for controlling the aforementioned dental instruments, which requires, among other things, only one, instead of a plurality of foot controls, water heaters, air and water filters, air and water pressure regulators, and air pressure gauges.

It is also an object of this invention to provide apparatus for controlling the aforementioned dental instruments, which includes a single foot control for regulating the rotary speed of the handpieces, the supply of water to the handpieces, and, where desired, the operation of a dental chipblower.

A still further object of this invention is the provision of apparatus for controlling the aforementioned dental instruments, which has sufiicient mobility and flexibility to be adaptable to existing dental operatories.

Another object of this invention is to provide apparatus for controlling the aforementioned dental instruments, which requires connection to only one water, one air, and one electrical source.

Further and additional objects will become manifest from a consideration of this description, the accompanying drawings, and the appended claim.

In one form, this invention comprises a compact unit adapted to be used on a counter top, in a cabinet, under a dental chair, or in any other convenient place in the dentists operatory. Installation is generally accomplished simply by connecting the apparatus of this invention to the instruments to be controlled and to conventional water, air, and electrical sources. The unit of this in- .vention includes a single foot control for regulating the pressure of the air supplied to the rotary handpieces and,

therefore, the speed of the handpieces; for controlling the supply of water to the handpieces; and, where necessary, for operating a dental chipblower. The unit also includes control means for limiting the pressure of the air and water supplied to the handpieces and filtering means for removing foreign particles from the air and Water and excess moisture from the air. A selector valve is provided so that the dentist by merely moving a selector knob or the like may direct the flow of air and water to whichever handpiece he desires to use. The unit is also equipped with an air pressure gauge for indicating the air pressure supplied to the handpieces. Occasionally, one or more of the handpieces may require oil lubrication of their turbine bearings. To accommodate such handpieces, an air line lubricator may be included in the apparatus of this invention.

For a more complete understanding of this invention, reference will now be made to the accompanying drawings wherein:

FIG. 1 is a perspective view of one embodiment of this invention.

FIG. 2 is a back plan view of the embodiment of FIG- URE 1.

FIG. 3 is an air and water circuit diagram of the disclosed embodiment.

FIG. 4 is an electrical circuit diagram of the disclosed embodiment.

FIG. 5 is a side elevational view of a combination air pressure switch and air filter drain with attached air filter, said combination pressure switch and filter drain being shown in vertical cross-section.

FIG. 6 is a vertical cross-sectional view taken along is provided. When the and adaptable for installation in almost any practicable place in the dental op-eratory. The foot control 12 18 generally positioned on the floor of the operato y veniently within the dentists range of OPCIZIHOII', ffxact position 'being dependent on the needs of the individual dentist.

Installation of the apparatus of the present 1nvent1on is accomplished simply by connecting the instruments to be controlled to appropriate fittings provided withm the unit and connecting the apparatus to suitable air, water, and electrical sources through cordage, which may extend from the rear of the unit 10 (see FIG. 2).

Before describing in detail the operation of the disclosed apparatus, it is first appropriate to set forth its use in general terms. The unit is energized by movement of the master switch 18 to the on position. When switch 18 is in this position, pilot light 20 will be illuminated. The supply of air to the handpieces and, consequently, the speed of the handpieces is controlled by the application of force to any part of the broad upper surface 22 of the foot control 12. This ability to power the handpieces by applying force anywhere on surface 22 affords to the dentist greater freedom of movement about the patient when utilizing the handpieces and, thus, saves the dentist considerable time and motion. The pressure of the air supplied to the handpieces varies in direct proportion to the amount of force applied to surface 22; however, to prevent damage to the handpieces from excessive speed, maximum air pressure is controlled by adjustments of the knob 24, located on the front or face plate of the unit 10. In the illustrated embodiment, clockwise rotation of the knob 24 will increase the amount of air pressure that may be supplied to the handpieces. Gauge 26 indicates the pressure in the air line at any given moment and may be used in conjunction with knob 24 for setting maximum air pressure. The gauge 26 also keeps the dentist apprised of the approximate speed of rotation of the handpiece since 'handpiece speed will vary in proportion to the amount of air pressure applied thereto. The supply of water to the handpieces is regulated both by the amount of air pressure furnished to the handpieces and by a push-on-push-off switch 28 positioned on the foot control 12. Until the air pressure exceeds a certain predetermined amount, usually a relatively low pressure, water will not be supplied to the handpieces; but at any air pressure, the flow of water to the handpieces may be terminated by actuation of switch 28 to the off position. Knob 30 on the face plate of the unit 10 regulates the rate of flow of the water, which rate in the disclosed embodiment is increased by clockwise movement of the knob.

Since the disclosed embodiment of the present invention is intended for use with two handpieces, one of which is capable of high rotary speeds,.the other of which operates at low speeds, a

control 32 is at its inner position, the air and water is directed to the high speed handpiece and the latter becomes operative; when the control 32 is pulled to its outer position, the low speed handpiece becomes operative.

Some handpieces have a separate air nozzle, called a chipblower, constructed into the head for blowing loose particles of tooth structure, moisture, and the like from caries during the excavating process and, thus, giving the dentist a better View of his work. Provision is made in the illustrated embodiment of the instant invention to ac: commodate this device. Positioned on foot control 12 is a hinged lever 34, which when actuated opens a valve and causes air to be supplied directly to the chipblower. Where the dentist does not use a chipblower, the push-onpush-off switch 28, shown in FIG. 1, controlling the water supply to the handpieces, may be disposed in the center of foot control 12 and actuated by the hinged lever 34 in the same manner as is the chipblower. When both a push-on-pushoff switch and chipblower are used, the

two position push-pull control 32 l tt i Operated by the hinged lever 34, because during dental operations the chipblower is generally used more frequently than the on-ofi switch and the lever, which 18 actuated from the center of the foot control 12;, ismore accessible than a switch or lever not centrally positioned.

Although not shown in FIGS. 1 or 2, air and water fittings are provided in the illustrated embodiment to accommodate a dental syringe. The location of these fittings is set forth in FIG. 3 and will be later described In great-er detail. When a three-way syringe is employed, the flow of water, air, or water spray is generally con trolled by selector means located on the syringe nozzle. The water used in the syringe generally requires heating, so that an electrical water heater is frequently used in conjunction with the syringe. This heater may be included within the electrical circuit of the present Invention by connection to one of the convenience outlets 36 located on the unit 10 (see FIG. 2). When so connected, the heater will be energized by the master switch 13. An additional water heater for heating the water supplied to the hand-pieces may also be connected to one of the convenience outlets 36 and controlled by the master switch 18.

Many manufacturers construct air turbine rotary instruments requiring continual oil lubrication of the turbine bearings. To accommodate such instruments, an oil lubricator has been included in the present embodiment. This lubricator is generally equipped with a sight feed dome for viewing the oil feed rate. As will be seen in FIGS. 1 and 2, the sight feed dome 38 is located on the top of unit 10 so that the dentist may easily keep apprised of the oil feed rate without having to remove the unit top.

FIG. 3 sets forth the air and water circuits in detail. Air is supplied to unit 10 through tubing or other suitable means from a conventional air source 40. It is then immediately directed through tube 42, usually constructed of a flexible plastic or rubber material, or other appropriate means, to a pressure regulating valve 44 in the foot control 12. The valve 44, which is normally closed, opens when force is applied to the surface 22 of the foot control 12. The air pressure on the output side of valve 44 will vary in direct proportion to the quantity of force applied to the foot control 12. The air under controlled pressure returns to the unit 10 through tube 46 and passes through a filter 48, which removes moisture and foreign particles from the air.

The filtered air flows from filter 48 to a combination pressure sensing unit 49 comprising pressure switch means 50 and filter drain means 52. Unit 4-9 is shown in detail in FIG. 5. By combining the pressure switch means and filter drain means into one unit 49, greater compactness of the overall unit It) is achieved.

When the pressure in the air-line equals or exceeds a predetermined amount, a diaphragm 51 of switch means 50 is actuated upward by the force of the air on its surface and causes a switch 53 to make electrical contact and actuate a solenoid valve 54, controlling the supply of water to the handpieces. The function of the solenoid valve 54 will be described hereinafter in greater detail. In the illustrated embodiment, it has been found satisfactory to provide for the actuation of diaphragm 51 and the consequent closing of the switch 53 at pressures in excess of about 6 to about 7.6 pounds per square inch. Adjustments of the latter pressure range may he made, but they will depend in part upon the lowest pressures at which the various handpieces may be success fully operated. If the air pressure necessary to actuate switch means 50 were to exceed the lowest operating pressure of the handpieces, then the handpieces when operated at minimum pressures would be deprived of a water supply even though the operator may desire to use water in such operations. The specific pressure range indicated above for actuating the pressure switch 50 has been adopted in contemplation of using the present invention with handpieces capable of satisfactory .put side of the lubricator.

operation at pressures as low as to 12 pounds per square inch.

The purpose of .the filter drain means 52 of unit 49, shown in detail in FIG. 5, is to dispose of the foreign matter removed from the air by the filter 48. Drain means 52 includes a valve 61, which is normally held I in an open position by the action of an upward force applied by a spring 56. A diaphragm 55, connected to valve 61, senses pressure from the main air line; and when the air pressure exceeds a predetermined amount, preferably 2 to 5 pounds per square inch, the downward force exceeds the upward force and closes valve 61. So long as the valve 61 is open and there is suflicient pressure in the line, the collected foreign matter, which has settled in the bottom or sump 57 of filter 48, will be blown from the filter through tubing 58 and out of the opening 59 provided in unit 49. It has been found that pressures of less than about 2 pounds per square inch are often insuflicientto adequately drain filter 48 and that pressures greater than about 5 pounds per square inch may cause objectionable noise.

The fully automatic air filter drain means described above saves the operator considerable time and motion and protects the filter against clogging. For example, if a manual filter drain valve were used in the apparatus of this invention .in lieu of the automatic drain means, the dentist would be required to operate this valve from time to time to keep the air filter free of foreign .materials. This latter operation would require a certain expenditure of time and motion, which, of course, would be unnecessary when the automatic drain means is used. Moreover, if the dentist inadvertently neglects to operate the manual drain valve, the filter may ultimately become clogged with foreign matter and impede the flow of air to the handpieces.

From the combination pressure sensing unit 49, the air is directed to a pressure regulator 60, the function of which is to limit the maximum air pressure which can be supplied to the handpieces. The pressure regulator 60 may be a standard poppet valve type and is operated by a manual control knob 24 located on the face of the unit 10-, as shown in FIG. 1. To the output side of the regulator 60 is connected a pressure gauge 62, which indicates the air line pressure at any give moment. The air passes from'the pressure regulator 60 to a selector valve 64, and from the latter to the handpieces.

As will be seen in FIG. 3, the selector valve 64 will accommodate two separate air lines for each handpiece, or a total of four air lines. Thus, a handpiece may not only be supplied with air to power the turbines, but also, where the handpiece is properly equipped, with air for use in conjunction with the water supplied to the handpiece to form a water spray coolant. When the present invention is used with handpieces which are not equipped to produce a water spray, the extra air lines are capped, and only one air line for each handpiece is used. v

Some air turbine rotary instruments require continual oil lubrication of the turbine bearings, which is accomplished by circulating oil with the air supplied to such 'instruments. Generally, such lubrication is necessary only for the high speed handpieces. Hence, when the present invention is used in conjunction with these instruments, an oil lubricator 66 is included in the air line which conveys air to the high speed handpiece. -As will be seen from FIG. 3, the lubricator 66 is connected to the outlet of valve 64 to which the handpiece would normally be connected if no lubricator were included in the system, and the hand piece is connected to the out- If lubrication of both handpieces is desirable, then the lubricator 66 may'be'placed on the air line between the pressure regulator 60 and the selector valve 64. For handpieces having auxiliary air lines to provide air for a water spray coolant, the

above arrangement would be suitable only when used with non-toxic lubricating oils, since the oil would be mixed with the water spray which is injected into the patients month. Most lubricating substances used today are edible and non-toxic; however, in those instances where they are not, each handpiece should have its own lubricator connected thereto in the same manner as lubricator 66 is connected to the high speed hand piece, as shownv in FIG. 3.

Water is supplied through any practicable water conduit means to unit 10 from a conventional source 70. It flows first through a two-way normally closed solenoid valve 71, which is energized and opened when the master switch 18 (see FIG. 1) is moved to the on position. This valve 71 prevents water from entering unit 10 until the latter is in actual operation. Thus, if water leaks develop in the unit 10, flooding of the operatory is prevented if, for example, the leaks develop at a time when the operatory is unattended. Moreover, if one of the devices in the system breaks downfor example, the syringe or a Water heaterrepair is simplified since the water supply to these devices may be terminated by. merely turning olf the master switch 18. It will be understood that the function of solenoid valve 71 could normally be achieved by a manual water valve; but then, of course, the automatic feature of the disclosed embodiment would not be retained. The water is directed from the solenoidvalve 71 to a filter 72, which removes any foreign material in the water, and then to a water heater, which is connected by suitable conduit means to the unit 10 by appropriate fittings 74 and 76. After the heated water returns to the unit 10, it flows through a conventional water pressure regulator 78, which controls the maximum amount of water that may be directed to the handpieces. The regulator 78 is manually controlled by knob 30 disposed on the front of unit 10, as shown in FIG. 1. From the pressure regulator 78, the water passes to another twoway normally closed solenoid valve 54. As noted earlier, the valve 54 is opened when the pressure switch means 50 in the air circuit makes electrical contact and energizes the solenoid. Hence, at air pressures of less than about 6 to about 7.5 pounds per square inch, the solenoid valve 54 will be closed and Will prevent water from passing to the handpieces. At greater pressures, the solenoid valve will open and the water will be directed through a selector valve 64 to the handpieces.

Valve 64, controlling the air and water supply to the handpieces, comprises in effect two three-way valves operated simultaneously by a single push-pull control 32. When the selector valve 64 is in the inner position, as illustrated in the disclosed embodiment, it supplies both air and water to the high speed handpiece; when it is in the outer position, both air and water are supplied to the low speed handpiece.

A suitable fitting 84 is provided on unit 10 for connection to the air line of a dental syringe. As will be seen from FIG. 3, a bleed line 86 leading to fitting 84 on unit 10 is branched from the main air line near the point where air is introduced into unit 10 from its original source 40. This bleed line 86 diverts air from the mainstream and supplies it to the dental syringe. Water is supplied to the dental syringe through bleed line 88, which directs the water to a suitable fitting 90 provided to accommodate a syringe water line. It should be noted that in the illustrated embodiment the water is heated prior to being supplied to the syringe. It may, nevertheless, be desirable to further heat this water by the use of an additional heater.

In addition to the pressure regulating valve 44 contained in the foot control 12, there may also be included an additional valve 92 for directing air to a dental chipblower. The valve 92 is opened by the application of force to the hinged lever 34 on foot control 12. A suitable fitting 94 is provided for connection with the tube or other appropriate means leading to the chipblower nozzle in the head of one of the handpieces.

FIG. 4 shows the electrical circuit used in the disclosed embodiment of the invention. The circuit includes a commercial power supply 96, a master on-off switch 1 8, a pilot light 20, a solenoid valve 71, convenience outlets 36, another solenoid valve 54, pressure switch means 50, and a push-on-push-otf switch 28. All of the electrical power supplied to the system is directed through the master switch 18, which is closed when at the on position. When the master switch 18 is closed, the pilot light 20 is illuminated, indicating that the former is at the on position, and the solenoid valve 71 is energized and opened, allowing water to enter the system. Since the push-on-push-oif switch 28, located in the foot control 12, is wired in series with the pressure switch means 50 and the solenoid valve 54, it may be used to terminate the flow of electrical energy to the solenoid valve 54 and to allow the dentist to prevent water from being furnished to the handpieces, even though the air pressure is great enough to cause the pressure switch means 50 to make electrical contact. The convenience outlets 36 are included in the electrical circuit so that, where desirable, the electric water heaters necessary for heating the water supplied to the handpieces and to the syringe may be connected to the outlets and, consequently, controlled by the master on-oif switch 18. It will be understood, of course, that in addition to the heaters, other electrical devices used in conjunction with the instruments controlled by the present invention may also be connected to the outlets 36 if practicable and desirable.

The foot control 12 of .the present invention, shown in perspective in FIG. 1, is shown in detail in FIGS. 6 and 7. It comprises in general a push-on-push-oif electrical switch 28 for controlling the water supplied to the handpieces; a valve unit 100, which contains therein an air pressure regulating valve 44 and a chipblower valve 92; a lever 110 for actuating the valve 44; and a hinged lever 34 for actuating the valve 92. The valve unit 100 is shown in vertical cross-section in FIG. 7.

Referring to FIG. 7, it will be seen that valve 44 is normally held in a closed position by springs 102 and 104, which apply an upward force on the valve. The closed valve is made airtight by the use of O-rings 105, 107, and 109, or other suitable sealing devices. When an external force is applied to the upper surface of Valve 44, it is actuated downward, causing air to be introduced into the system through inlet 106 and to be directed to the handpieces through outlet 108. The amount of air supplied to the handpieces Will be dependent upon the distance that valve 44 is depressed, which, of course, relates to the force applied to the upper surface of valve 44. Valve 44 is actuated by a lever 110, which is operated by the application of force to the surface 22 of foot control 12. An annular element 112 is provided to prevent upward movement of the lever 110. Thus, when force is applied to one side thereof of the lever 110, the opposite side will not move upward and compensate for this force, so that the dentist may step on substantially any portion of surface 22 of foot control 12 to actuate valve 44.

Also shown in FIGS. 6 and 7 is a valve 92 for-operating a chipblower. As will be seen in FIG. 7, this valve 92, like valve 44, is spring actuated and is normally held in a closed position. Air-tightness is afforded to valve 92 by O-rings 111, 113, and 115, or other suitable sealers. Air enters the system through inlet 106; and when valve 92 is depressed, the air is directed to the chipblower through outlet 114. Actuation of valve 92 is accomplished by the application of an external force to a lever 34, which rotates about a hinge 116.

It will be obvious from the foregoing description and the drawings that many modifications of the disclosed embodiment, including those already mentioned, may be made without departing from the spirit and scope of the present invention. One such modification may be to use instead of the disclosed selector valve, one comprising two three-way solenoid valves actuated by an electrical switch. With respect to the selector valve, it also should be understood that where more than two handpieces are employedfor example, where a handpiece with a miniature head is used in addition to the conventional high and low speed handpieces-the use of a selector valve equipped to accommodate the additional handpieces is contemplated. Another modification may be to substitute for the pressure switch and solenoid valve other means for controlling the handpiece water supply, which, like the disclosed combination, would be dependent upon the pressure of the air supplied to the handpieces. Such means may comprise, among others, an air-operated water valve, although the latter type valve would not be readily adaptable for operation by a foot control, and would, therefore, not be as expedient as the means disclosed in the illustrated embodiment. A further modification may be the elimination of the air or water filters if suitable air or water filtration is provided prior to the entry of the air and Water into the control unit.

Without further elaboration, the foregoing will so fully explain the character of this invention that others, by applying current knowledge, may readily adapt it for use under varying conditions of service, while retaining certain features, which may properly be said to constitute the essential items of novelty involved and which are, therefore, intended to be defined and secured by the following claim.

What is claimed is:

In apparatus for controlling the operation of air turbine-driven dental handpieces and a dental chipblower, which apparatus is adapted to receive water, air, and electrical energy from conventional sources, a foot-operated control comprising: a base adapted to rest on a generally flat surface; valve means connected to said base for controlling the air pressure supplied to the handpieces; a lever for actuating said valve means, said lever comprising a movable upper element, the underside of which engages said valve means, and retaining means for preventing upward movement of said upper element, whereby when a downward force is applied to a portion of said upper element said portion will be actuated downward and depress and open said valve means, whereas the opposite portion of said element will be prevented from upward movement; a second valve means connected to said base for directing air to the chipblower; a second lever for depressing and thereby opening said second valve means, said second lever having a hinge attached to one end, said hinge connecting said second lever to said upper element of said first lever, said second lever being rotatable about said hinged end, the rotary axis of said hinged end being substantially parallel to said base; and an electrical push-on-push-ofi switch connected to said base, which switch may be caused to make electrical contact and to energize and open a solenoid valve controlling the supply of water to the handpieces.

References Cited by the Examiner UNITED STATES PATENTS 1,085,159 1/1914 Raab 137-546 X 2,984,008 5/1961 Weisberg 32-28 3,039,193 6/1962 Williams 32 28 3,084,439 4/1963 Staunt.

3,106,021 10/1963 Borden 328 3,129,511 4/ 1964 Williams 32-28 RICHARD A. GAUDET, Primary Examiner. ROBERT E. MORGAN, Examiner. 

